After a very long test (4 weeks) in which I compared 3 different tube amps:2 push pull designs: McAlister MB-130 monos, Rogue Audio M-150 monos and one SET design: JAS Audio Array 2.1, 300B/805 SET, I recently purchased this latest one and I believe that I am at the end of my journey.

I have real hard time moving my ass from the couch and stop listening.This SET amp had me at hello...What is interesting is that what I was trying to fix in my system was some solid state hardness and some leanness in the mid range, attributed to the Joule LAP-150 Mk II and the Bryston 4B combo but I discovered that this is not what SET in general and 300B in specific is all about:I discovered that what 300B is all about is threefold: [b][black]Immediacy, intimacy and spatial information[/black][/b] which all amount to what I would like to call:"The sound bubble effect".It is like another veil was lifted between you and the music. When I got the amp for a long loan it had stock Shuguang and Electro-Harmonix tubes in it and with these unimpressive tubes (especially the lackluster 805s) the mid range was to-die-for, the highs sweet but slightly rolled off and the bass a bit slow (exactly like in the review: http://www.6moons.com/audioreviews/jas3/array21.html).

Even as it was, I fell in love and for that amazing mid-range I would forgive the soft bass and the limited highs (kind of like Quad ESL 57 lovers) BUT than I dared to change the stock tubes to some very rare and coveted NOS and new high end new production tubes:1. Input tube - Sylvania JHS 5751WA Triple Mica, Black plate from the 50s:

4. Output Tubes - 805s changed to RCA NOS 1940s (these usually go for $550-700 on the web but I got a used pair at $200)

THE AMP LITERALLY TRANSFORMED

Soft bass? no way. Lack of scale? in your dreams. Rolled Off highs? forget it.Limited dynamics and slight 300B slowness (when it has to drive a not SET friendly set of speakers i.e.)? Non of that.

All the mid-range magic was there plus some: more transparent and better macro and micro-dynamics but than the most interesting thing is my realization that this is not a romantic sound per-se, this is an effortless, airy, ultra revealing yet sweet, smooth and ambient sound presentation with intimacy and immediacy like I have never heard in my life.

This amp, per the reviewer, works better with a decent pre-amp (matching, as always, has to be done carefully - in my case the Joule-Electra LA-100 Mk III worked better than the LAP-150 Mk II)

and some others but mostly significantly more expensive than the U$3,000 JAS.It is certainly a cost effective way to enter the magical SET world even without having a 100+ dB efficient speakers with 16 ohm impedance.

Another jewel I was waiting patiently for (had an agreement with my wife to wait until my 40th birthday) was the Oracle Delphi Mk II with the Alphason Xenon MCS arm and Dynavector 17D3:

Best description of what this turntable is all about is "CD Player with soul".

Once its suspension is set up (hair tearing experience not for the impatient or weak at heart...[:p]) Noise floor is extremely low, detail retrieval is uncanny, highs and lows are extended and clean and vibration handling is excellent: you can jump up and down near it, knock with your finger on its acrylic base and nada, which means no muffling of the bass like in many mass loaded tables, due to back vibration from the plate: This translates to a super clean sound but never analytical. No surprise this turntable's design, which was designed by one of NASA's Apollo landing gear designer, has never really changed in the last 30 years - "if it ain't broke don't fix it":http://www.enjoythemusic.com/superioraudio/equipment/1006/oracle_delphi_mkv.htm